1. Technical Field
The present disclosure relates to integrated circuits, and more particularly to updating data in a non-volatile data storage device.
2. Related Art
Integrated circuits (ICs) utilize non-volatile data storage (“memory”) to store data that must be retained even if power is removed from the IC. In many applications, the data stored in the non-volatile memory is updatable by the IC. For example, a device may include an IC to tally the number of occurrences of an event (or events) through the lifetime of the device. The IC may update event occurrence data in the non-volatile memory each time the event occurs. The updated data is retained when the device is powered down and the event count can be resumed when the device is powered-up again. An example of updateable data is a printer page count, i.e., tallying the total number of pages printed through the life of a printer. The most recent printer page count must be retained when the printer is turned off or unplugged. Updateable data may also include universal serial bus (USB) endpoint data, external component identification data, and/or many other types of data.
ICs utilize rewritable non-volatile memory to store updateable data that must be retained when the device is powered down. Examples of rewritable non-volatile memory include electrically erasable programmable read only memory (EEPROM), flash memory, and ferroelectric random access memory (FeRAM). Rewritable non-volatile memory may be incorporated into an IC when it is manufactured or may be added to a system as a discrete element. In many applications, only a relatively small amount of rewritable non-volatile memory (e.g., 2 Kbytes) is required to store all of the updateable data through the device's life. However, extra processing steps are required to incorporate even a small amount of rewritable non-volatile memory into an IC. These extra processing steps often increase the cost of the IC disproportionately. Adding rewritable non-volatile memory as a discrete element in a system is also expensive and is often not an option. An improved approach is desirable.